consider dependencies of client mods also as client mods to prevent spilling them into the world save

Plugin.ClientModLoader/ModInjector.cs

@@ -1,4 +1,5 @@
-using System.Reflection.Emit;
+using System.Collections.Immutable;
+using System.Reflection.Emit;
 using HarmonyLib;
 using Sandbox.Definitions;
 using Sandbox.Engine.Networking;
@@ -26,7 +27,31 @@ internal static class ModInjector
     [HarmonyPostfix]
     private static void DownloadModsBlockingPostfix(List<MyObjectBuilder_Checkpoint.ModItem> mods, List<MyObjectBuilder_Checkpoint.ModItem> __state)
     {
-        foreach (var mod in mods)
+        var worldMods = __state.Select(b => b.PublishedFileId).ToImmutableHashSet();
+        var resolvedMods = mods.ToImmutableDictionary(b => b.PublishedFileId);
+        
+        // list of selected mods which are resolved
+        var requestedMods = mods.IntersectBy(Mods, b => b.PublishedFileId)
+            .ToDictionary(b => b.PublishedFileId);
+        
+        // add dependencies of requested mods
+        // but skip if those are also requested by world we're loading in
+        foreach (var dependency in requestedMods.Values
+                     .SelectMany(b => b.GetModData().Dependencies)
+                     .Distinct().ToArray())
+        {
+            if (worldMods.Contains(dependency))
+                continue;
+            
+            requestedMods.TryAdd(dependency, resolvedMods[dependency]);
+        }
+        
+        // add resolved client mods and their exclusive dependencies
+        AdditionalFilledModItems.AddRange(requestedMods.Values);
+        
+        // upsert world mods by resolved ones excluding our client ones and their exclusive dependencies
+        // so world mods is only populated by dependencies of original world mods
+        foreach (var mod in mods.ExceptBy(requestedMods.Keys, b => b.PublishedFileId))
         {
             var index = __state.FindIndex(b =>
                 b.PublishedFileId == mod.PublishedFileId && b.PublishedServiceName == mod.PublishedServiceName);
@@ -37,8 +62,6 @@ internal static class ModInjector
                 stateMod.SetModData(mod.GetModData());
                 __state[index] = stateMod;
             }
-            else if (Mods.Contains(mod.PublishedFileId))
-                AdditionalFilledModItems.Add(mod);
             else
                 __state.Add(mod);
         }
@@ -104,7 +127,7 @@ internal static class ModInjector
         foreach (var mod in Mods)
         {
             //avoid duplicates
-            if (mods.FindIndex(m => m.PublishedFileId == mod) != -1)
+            if (mods.Exists(m => m.PublishedFileId == mod))
                 continue;
 
             mods.Add(new MyObjectBuilder_Checkpoint.ModItem(mod, "Steam"));